How big of a difference is a 8600GT vs a 8800GTX? Is it going to be night and day? I want to be able to play games on this thing for atleast a couple of years without everything be on low settings. I also think ill be using this as a dvr of sorts when Im not using it by hooking it up to a external hdd and using a usb tuner, any problem with the 8600gt doing this compared to the gtx?